1. Field of the Invention
The present invention relates to a method of mounting a semiconductor chip which is suitable for manufacturing an electromagnetic wave readable data carrier that functions as a flight tag, a label for physical distribution management, a ticket for an unmanned wicket and others, particularly relates to a method of mounting semiconductor chip in which a bare semiconductor chip can be mounted on a circuit board at a low cost by a flip-chip connecting method. The present invention also relates to a circuit board for flip-chip connection and a method of manufacturing the same. In addition, the present invention relates to an electromagnetic wave readable data carrier and a method of manufacturing the same, and an electronic component module for an electromagnetic wave readable data carrier.
2. Description of the Related Art
For this type of electro magnetic wave readable data carrier, a flight tag disclosed in Japanese Patent Unexamined Publication No. Hei. 6-243358 for example is known. It is estimated that the flight tag will be used for the management of passenger""s baggage at an airport as a throwaway tag in near future. At that time, in the case of a worldwide airline company, the enormous demand such as 8.5 million pieces per month can be expected by only the company. Therefore, as to this type of flight tag, the establishment of mass production technology at an extremely low cost is desired.
The flight tag disclosed in the patent application is composed by mounting a curled conductive pattern to be an antenna coil and IC components to be a send and receive circuit, a memory and others on the single side of a rectangular substrate made of a PET film.
The body of the flight tag that holds the curled conductive pattern to be an antenna coil can be formed by selectively etching copper foil and aluminum foil respectively coated on the single side of the PET film by etching processing. Therefore, a continuous production line by roll to roll (RTR) can be readily realized by a resist formation process by well-known photolithographic technology and the succeeding wet etching process and others. In the meantime, circuit components such as a send and receive circuit and a memory to be mounted on the body of the flight tag are integrated in one chip using semiconductor integration technology.
These applicants propose that a bare semiconductor chip is first moduled by mounting the bare semiconductor chip composing the send and receive circuit, the memory respectively described above and others on a thin insulating piece (a type of circuit board) and then the productivity of a flight tag is enhanced by bonding the electronic component module on a PET film composing the body of the flight tag.
As for an electronic component mounted sheet, the advanced thinning of which is requested, such as the electronic component module bonded to the flight tag, a flip-chip connection method in which a bare semiconductor chip is directly mounted on a circuit board is often proposed.
An example of the flip-chip connection method (hereinafter called a first related art type method) is shown in FIG. 14. In the first related art type method, a protruded terminal for connection (hereinafter called a bump) b is formed on the bottom electrode (not shown) of a semiconductor chip a and after the bump b and an electrode area d of a wiring pattern on a circuit board c are positioned, both are connected via joining material e such as solder and conductive paste.
In the first related art type method, a problem is pointed out such that the manufacturing cost is increased because (1) a process for supplying and hardening the joining material e for connecting the bump b and the electrode area d of the wiring pattern is complex, (2) an insulating resin f called underfill is filled between the chip a and the board c so as to seal a bump connection portion between the bump b and the electrode area d and thereby to acquire the reliability in the moisture-proof of the bump connected part and strength for mounting the semiconductor chip and (3) a process for filling and hardening the insulating resin f to be underfill is required.
Another example of the flip-chip connection method (a second related art type method) is shown in FIG. 15. The second related art type method is proposed to solve the problem of the first related art type method and a bare semiconductor chip is mounted on a circuit board using an anisotropic conductive sheet proposed in Japanese Patent No. 2586154.
In the second related art type method, an anisotropic conductive sheet g in which conductive particulates are dispersed in thermoplastic or thermosetting resin is put between a bare semiconductor chip a and a circuit board c, and the resin is made to flow by thermocompression bonding, so that electric connection in the direction of the thickness is acquired by conductive particulates h put between a bump b and an electrode area d of the wiring pattern.
According to this method, there is effect that the positioning of the circuit board with the wiring pattern when the semiconductor chip is mounted on the circuit board can be relatively roughly performed. In addition, time when resin is hardened is short, for example 10 to 20 seconds, sealing material such as under fill is not required to be used, and the manufacturing cost can be reduced. To the contrary, problems are further pointed out such that (1) the anisotropic conductive sheet g is relatively high-priced, (2) the anisotropic conductive sheet cannot be used for a board without heat resistance because the high temperature of 200xc2x0 C. or more is required for hardening the sheet, (3) it takes 10 to 20 seconds to harden the resin though it is a relatively short time, and it is difficult to further simplify and speed up the process and (4) the reliability of connection is low because electric connection between the bump and the wiring pattern depends upon the contact of conductive particulates dispersed in the resin.
The invention is made to solve the problems in the related art type flip-chip connection method and the object is to provide a method of mounting semiconductor chip by a flip-chip connection method in which a semiconductor chip can be mounted on a circuit board promptly, electrically and mechanically securely and further at a low cost.
Also, another object of the invention is to provide a circuit board for flip-chip connection suitable for the above-mentioned mounting method.
Also, further another object of the invention is to provide a method of manufacturing a circuit board for flip-chip connection in which the above-mentioned circuit board can be manufactured simply and at a low cost.
Further, furthermore another object of the invention is to provide an electromagnetic wave readable data carrier and a method of manufacturing the same in which an electromagnetic wave readable data carrier that functions as a flight tag, a label for physical distribution management, a ticket for an unmanned wicket and others can be produced at a low cost in a mass.
Also, further another object of the invention is to provide an electronic component module for an electromagnetic wave readable data carrier.
The person skilled in the art will easily understand further another object and the effect of the invention by referring to the description of embodiments and others.
A method of mounting a semiconductor chip according to the invention is provided with a process for pushing a melted thermoplastic resin coat aside by pressing a bump of a bare semiconductor chip on the melted thermoplastic resin coat applying an ultra sonic wave in a state in which the thermoplastic resin coat covering an electrode area on a wiring pattern is heated and melted and touching the bump and the electrode area, a process for bonding the bump and the electrode area by continuously applying an ultrasonic wave in a state in which the bump and the electrode area are touched and a process for cooling and solidifying the melted thermoplastic resin and bonding the body of the bare semiconductor chip on a circuit board.
As clear from the description that in a state in which the thermoplastic resin coat covering an electrode area on a wiring pattern is heated and melted, a thermoplastic resin coat is formed beforehand in an electrode area on a wiring pattern of a circuit board used in the invention. This coat may also cover only an electrode area of a wiring pattern and may also cover the overall surface of a wiring pattern.
Also, a phrase, an electrode area on a wiring pattern described above means a fixed small area on a wiring pattern including a position for a terminal of an electronic component and others to be connected. In this electrode area, a part generally called a land and others on the wiring pattern is included.
Also, words, xe2x80x9cheated and meltedxe2x80x9d mean both a state that the thermoplastic resin coat is heated and melted and a state that it is heated and softened to some extent. Further, it is desirable that thermoplastic resin described above has a satisfactory characteristic as an adhesive.
According to such configuration, action and effect are acquired that (1) secure electric conduction is acquired because the junction of the bump and the electrode area is diffused junction by an ultrasonic wave, (2) moisture-proof is satisfactory because the junction is sealed with resin, (3) mechanical mounting strength to pulling and others is high because the semiconductor chip and the circuit board are bonded when the thermoplastic resin is hardened, (4) electric conduction and mechanical bonding are simultaneously enabled in a short time, (5) the manufacturing cost is low because a process for special sealing and bonding and bonding material are not required and (6) the surface of the board is nevermore sticky than required in heating because no thermoplastic resin coat exists in a part in which the surface of the board is exposed.
Also, the overall surface of the wiring pattern of the circuit board for flip-chip connection according to the invention is covered with a thermoplastic resin coat.
According to such configuration, as the overall surface of the wiring pattern is covered with a thermoplastic resin coat in case the circuit board described above is used for the mounting method described above, sealed structure satisfactory in moisture-proof and bonded structure high in tensile strength are acquired.
Also, in a method of manufacturing the circuit board for flip-chip connection according to the invention, for an etching mask used when the wiring pattern is formed by etching processing, thermoplastic resin is used.
According to such configuration, as an etching mask used in etching processing for forming the wiring pattern is used for the thermoplastic resin coat covering the overall surface of a conductive pattern as it is, a special coat formation process is not required and much labor is not required, and therefore the manufacture at a low cost can be realized.
Also, in a method of manufacturing an electromagnetic wave readable data carrier according to the invention, the body of a data carrier in which a curled conductive pattern composing an antenna coil is held on thin or sheet insulating base material and an electronic component module in which a bare semiconductor chip composing a send and receive circuit, a memory and others is mounted on a wiring pattern of a thin or sheet circuit board are integrated.
In the data carrier manufacturing method, a process for manufacturing the electronic component module in which the bare semiconductor chip is mounted on the wiring pattern of the thin or sheet circuit board is mainly characteristic.
That is, in the process for manufacturing the electronic component module, a subprocess for pushing a melted thermoplastic resin coat aside by pressing a bump of the bare semiconductor chip on the melted thermoplastic resin coat applying an ultrasonic wave in a state in which the thermoplastic resin coat covering the electrode area on the wiring pattern is heated and melted and touching the bump and an electrode area, a subprocess for bonding the bump and the electrode area by continuously applying an ultrasonic wave in a state in which the bump and the electrode area are touched and a subprocess for cooling and solidifying the melted thermoplastic resin and bonding the body of the bare semiconductor chip on the circuit board are included.
According to such configuration, the electromagnetic wave readable data carrier that functions as a flight tag, a label for physical distribution management, a ticket for an unmanned wicket and others can be produced at a low cost in a mass owing to action and effect that (1) secure electric conduction is acquired because the junction of the bump and the electrode area is diffused junction by an ultrasonic wave, (2) moisture-proof is satisfactory because the junction is sealed with resin, (3) mechanical mounting strength to pulling and others is high because the semiconductor chip and the circuit board are bonded when the thermoplastic resin is hardened, (4) electric conduction and mechanical bonding are simultaneously enabled in a short time, (5) the manufacturing cost is low because a process for special sealing and bonding and bonding material are not required and (6) the surface of the board is never more sticky than required in heating because no thermoplastic resin coat exists in a part in which the surface of the board is exposed.
Also, the overall surface of a wiring pattern of a circuit board used in the manufacturing process of the electronic component module according to the invention is covered with a thermoplastic resin coat.
According to such configuration, as the overall surface of the wiring pattern is covered with the thermoplastic resin coat in case the above-mentioned circuit board is used in the electronic component module manufacturing process, sealed structure satisfactory in moisture-proof and bonded structure high in tensile strength are acquired.
Also, in a circuit board manufacturing method according to the invention, thermoplastic resin is used as an etching mask used when a wiring pattern is formed by etching processing.
According to such configuration, as the etching mask used in the etching processing for forming the wiring pattern becomes a thermoplastic resin coat covering the overall surface of a conductive pattern as it is, a special coat formation process is not required and much labor is not required, and therefore the manufacture at a low cost can be realized.
Also, in a method of manufacturing an electromagnetic wave readable data carrier according to the invention, the body of a data carrier in which a metallic foil pattern composing an antenna coil is held on thin resin base material, and an electronic component module in which a bare semiconductor chip composing a send and receive circuit, a memory and others is mounted on a aluminum foil wiring pattern on the surface of thin resin base material are integrated.
In the electromagnetic wave readable data carrier manufacturing method, a process for manufacturing the electronic component module in which the bare semiconductor chip is mounted on the aluminum foil wiring pattern on the surface of the thin resin base material is mainly characteristic.
That is, in the process for manufacturing the electronic component module, a subprocess for pushing a melted thermoplastic resin coat aside by pressing a bump of the bare semiconductor chip on the melted thermoplastic resin coat applying an ultrasonic wave in a state in which the thermoplastic resin coat covering an electrode area on the aluminum foil wiring pattern is heated and melted and touching the bump and the electrode area, a subprocess for bonding the bump and the electrode area by continuously applying an ultrasonic wave in a state in which the bump and the electrode area are touched and a subprocess for cooling and solidifying the melted thermoplastic resin and bonding the body of the bare semiconductor chip on the circuit board are included.
Also, the overall surface of the aluminum foil wiring pattern of the circuit board according to the invention is covered with a thermoplastic resin coat.
Also, in the circuit board manufacturing method according to the invention, thermoplastic resin is used as an etching mask used when the aluminum foil wiring pattern is formed by etching processing.
In a preferred embodiment of the invention, for thermoplastic rein, polyolefin resin or polyester resin is used.
Action and effect can be desired by using such resin such that the resistance to a chemical satisfactory for an etching mask, and satisfactory junction strength between a metallic bump on the side of the semiconductor chip and a metallic electrode area on the side of the wiring pattern are acquired. That is, polyolefin resin is provided with satisfactory resistance to alkaline etchant such as NaOH or polyester resin is provided with satisfactory resistance to acid etchant such as FeCl2. In addition, these resins are also excellent in an adhesive property.
Further, an electronic component module for an electromagnetic wave readable data carrier, according to the invention, comprises: a circuit board having a wiring pattern with an electrode area and a thermoplastic resin coat covering the electrode area of the wiring pattern; and a semiconductor chip mounted on the circuit board, said semiconductor chip having a bump at a side of the circuit board thereof. The bump of the semiconductor chip penetrates the thermoplastic resin coat and directly bonds with the electrode area of the wiring pattern.
In addition, an electromagnetic wave readable data carrier, according to the invention, comprises: a body of a data carrier including an insulating base material and a conductive pattern held on the insulating base material; and an electronic component module including a circuit board and a semiconductor chip mounted on the circuit board, said circuit board having a wiring pattern with an electrode area and a thermoplastic resin coat covering the electrode area of the wiring pattern, said semiconductor chip having a bump at a side of the circuit board thereof, the bump of the semiconductor chip penetrating the thermoplastic resin coat and directly bonding with the electrode area of the wiring pattern, wherein said electronic component module is manufactured by a method comprising: heating and melting the thermoplastic resin coat of said circuit board; pressing the bump of said semiconductor chip on the thus melted thermoplastic resin coat while applying an ultrasonic wave to the bump so that the bump penetrates the melted thermoplastic resin coat and brings into contact with electrode area; bonding the bump and the electrode area by continuously applying the ultrasonic wave to the bump bringing into contacted with the electrode area; and cooling and solidifying the melted thermoplastic resin coat so as to securely mount said semiconductor chip on said circuit board.